Process of producing rubber compositions and vulcanization product therefrom.



m Mme oorrranv, F AKEtUN, (Obllltlt, A CG).

Ulifll'flr- RUETBEIEL GUIVIPUEETIQNE AND VULGANIZATICDN PEODUGT THEELE'ERQEL Cassia-LY;

o brewing.

To all whom may concern I 7 Be it known that l, Roninrr thl-llAn'roNe,

, a citizen oil the United States, residing at ice All

lid

Akron, in the county of Summit and State of Ohio, have invented a new and useful. Process of Producing ldubber Compositions and Vulcanization Product 'llhereirom, of which the following is a specification.

My invention relates to the art ot' producing rubber compositions and will be fully understood from the following specification. lln the manufacture of rubber products a large variety oi ingredients are employed and in every instance it is desirable to secure a uniform and homogeneous mixture of these ingredients, both with one another and with the rubber, in order that the vulcanized product may be of highest quality. My in: vention is particularly concerned with a method or procedure by'which the ingredients oi the composition may be incorporated into and disseminated through the rubber mix in the iinest, practical state of subdivision and in such a manner as to secure true homogeneity. This end I find to be best attained by the use of a liquid carrier for the ingredients.

lit is a well understood fact that the action of a solvent liquid upon a solid. is to disintegrate that solid and break it t into excessively small particles, these particles when disseminated through the liquid being said to dissolve therein. For example it is believcd that some substances of which the soluble carbohydrate sugar may be taken as an illustration, disintegrate into their ultimate molecules in the presence of a suiiiciently large volume 01: water, so that in a sugar solution the sugar exists in the most extreme state of physical subdivision of which it is capable, ()ther substances, such as glue for instance, when dissolved in water do not appear to be subdivided to the same extent as the sugar particles mentioned, but on the other hand they enter into some spe cies ot combination with the water by which they become enormously swollen or distended and it subjected to a grinding action in this distended condition may be more finely divided than is possible in handling the dry product, in still other instances there may tipceiiieatien of Letters fbatent.

l atentedei ori rare,

duplication filed March so, W333. He. wanna eiiiected in the case or" the sugar solution but nevertheless very decided, unaccompanied by any noticeable combination oi the solid with. the solvent. Illustrations of this species of action are found in colloidal solutions or metals such as gold and platinum in water and inv such materials as arsenic sulfid, clay, and the like= Finally the solvent may have comparatively little disinte grating power upon the solid but nevertheless still shows a distinct power of maintaining the solid in a fine state of subdivision when this subdivision has been effected, or at least of enormously decreasing the rate of association of the particles of a finely divided substance Thus for example when coarse materials of the natureot barytes are suspended in water, each individual particle is retained in its separate state, agglomeration of the particles being prevented so long as the water is present in reasonable amounts.

it is therefore true that a carrier liquid is in general useful to some extent, either in eii'ecting disintegration of a solid substance or preventing or retarding the reassociation of disintegrated particles which have been reduced to a tine state of subdivision byany means. From this standpoint alone therefore the use of a carrier liquid is advantageous in the mixing of rubber compositions. A iurther important advantage arises from the fact that the liquid carrying the solid with it may be disseminated through the rubber with a relatively small amount of mechanical working, thereby avoiding the breaking down and loss of tensile strength oi the rubber which results from the excessive working sometimes neces sarily resorted to in order to efi'eot thorough dissemination of a solid constituent, The carrier liquid is also of particular advantage in the case of solid ingredients which form true solutions such the sugar solution mentioned, or which form colloidal solutions either as emulsion colloids or as suspension colloids and where relatively small percentages of the particular ingredients areernployed By the increase in bulk or (ill too

vo-lunne resulting from the action of the of subdivision than the reduced to.

carrier liquid the diflicultyof effecting thorough dissemination of these relatively small percentages through the mass of the rubber mix is substantially lessened.

. I have found that for the majority of materials employed for mixing with the rubber gum in the manufacture of rubber products, water forms the most desirable carrier liquid, both because of its che'apness and because of the fact that it does not act upon the rubber in the mix. It must be understood, however, that other carrier liquids may be employed without departure from the basic principles of my invention.

After the mix has been satisfactorily made the water or other carrier liquid must be removed, it being well known that any large percentage of vaporizable matter such as water in'the ordinary rubber mix is highly disadvantageous in that vapors are evolved during vulcanization and the vulcanized product is thereby rendered porous. I'find' that the water may readily be removed, however, either by vacuum drying or by the use of a current of air or other inert gas, the expense of the treatment being far outweighed by the advantages resulting from the use of the carrier liquid in mixingthe composition.

As specific examples of the uses to which my invention may be put the following may be enumerated.

- Alumina.

ing, the vulcanizedlproduct evidences in all natureof the mixing process.

ofits physical properties the more perfect Colloidal metals.

What has been said of alumina is also quite true of certain metals, such as iron and lead. These metals, when reduced to -avery fine powder'by grinding, do not become composition ingredients which have any great commercial value. If, however, are obtained in colloidal form and are added to the rubber in the form of a'thick paste,

' using water or a dilute colloidal solution of glue or gelatin as *the'liquid medium; the

moisture subsequently removed'by drying .65

before the other ingredients are added a these metals very decided improvement will be obtained in the quality of the finished product.

Bah tee.

It has long been known that baryt'es prepared by grindingthe mineral as found in nature is inferior to barytes precipitated from an aqueous solution, in the manufacture of rubber products, this inferiority being due to the imperfect material effected by dry grinding. The advantages gained by the initial precipitation are to a large extent lost, however, by the subsequent drying of the precipitate, the

fine particles agglomerating or reassociating to a considerable extent so that remain finer than the dry-ground product they are nevertheless relatively coarse as compared with the suspended precipitate. In accordance with my invention I may avoid the reassociation of the finely divided suspended precipitate by incorporating the original suspension directly in the rubber mix. By the use ofthe precipitate as prepared in a dilute solution, the fineness of subdivision of the while they the' precipitate being to a considerable extent a function of the dilution, even better results may be secured. A further improvement may be effected by adopting measures to prevent the coalescence of the precipitate within the solution or suspension. This effect may be obtained by causing the precipitation to take place in the presence of glue, gelatin or similar emulsion colloids. action of such colloids appears to be similar to that of an emulsifying agent, the nascent particles of the precipitate being instantly coated with the glue or the like, which coatingserves to prevent coalescence.

Glue. v The alumina and barytes previously mentioned may be called irreversible colloids in that the particles should beretained in the solution in which they are produced until the completion of the mixing process in order to prevent their coalescence into larger masses which could not again be reduced to the form of a suspension colloid or suspensoid without considerable manipulation. O-n

the other hand materials such as animal glue colloids, in that may be called reversible after having been reduced to the solid form Zthey may be again converted'into emulsions by the simple addition of water.

Commercial glue reduced to the finest state of subdivision possible by dry grinding is unsatisfactory as a constituent of the rubber composition in that it is practically impossible to-secure a mixture so homogeneous that small particles of the glue will not re main visible upon examination under the microscope. If, however, this glue be treated with water so that it becomes swollen and. forms a gel, perfect mixing may be The effected by the ordinary methods and examination of the final product either before or alter vulcanization fails to show any lack of homogeneity, Furthermore it is possible by this method producing the mixture to secure a final vulcanized product exhibiting physical properties unobtainable by the known methoda My invention is particularly valuable in the en'iployment of gel-forming emulsoids such as glue as compounding ingredients in that the particles which are once separated from one another in mixing have no tendency to again coalesce should they adventitiously come into contact at some later stage of the mixing,

Zinc om'al and other insoluble, nowcollo'idal, uncmulmfiablc compound mg ingrcdwm'ss.

The use of a carrier liquid with such ingredients as .zinc oxid would appear to involve no action other than the purely physical one of facilitating the dispersion of the solid through the mixture. The technical results and advantages which follow from this purely physical action are however of considerable importance and warrant the use of my invention for mixing ingredients such as those named upon which the carrier liquid exerts little or no dissociating action. If such materials be incorporated into the rubber mix by the known methods the most thorough mechanical manipulation or kneading of the mix must be resorted to to effect any satisfactory dissemination, the material tending to associate itself into lumps which must be most carefully broken up if a high grade product is to be obtained. ()n the other hand long continued mixing or kneading operations tend to affect the properties of the rubber gum itself in an in jurious manner and a nice balance must therefore be maintained between unsatisfactory mixing and overworking.

By the use of a carrier liquid serving as a dispersing medium for these ingredients en tirely satisfactory results can be secured and all danger of overworking the rubber is obviated. it is not necessary in the use of zinc oxid or the like to employ large quantities of the carrier liquid, an amount or liquid sufficient to form a semi-fluid paste being quite sutlicient for practical purposes.

While T have described in considerable detail the theories which I believe to underlie my invention, and have set forth the specific manner of operation and some of the results which can be obtained in the use of specific constituents according to the invention, it.

will be understood that my invention is not dependent upon the soundness of the theo ries which it have advanced nor'limited to the specific materials or methods of manipulation named, except in so far as such limitations are included within the terms of the accompanying claims in which it is my intention to claim all novelty inherent in my invention as broadly as is permissible in yiew of the'prior art.

What ll claim as new and desire to secure by Letters Patent is 1. The process of forming a rubber composition which consists in adding to rubber a volatilizable carrier liquid holding a composition ingredient in a finestate of subdivision, mixing the carrier liquid and the ingredient held thereby with the rubber, volatilizing the carrier liquid, whereby the ingredient is left disseminated throughout the mix, and heating the mix with a vulcanizing agent to eii'ect vulcanization.

2. The process of forming a rubber composition which consists in adding to rubber, water holding a composition ingredient in a fine state of subdivision, mixing the water and the ingredient held thereby with the rubber, volatilizing the water, whereby the ingredient is left disseminated through the mix and heating the mix with a vulcanizing agent to effect vulcanization. i 3. The process of forming a rubber composition which consists in addingto rubber a colloidal solution of a composition ingredient, mixing the solution with the rubber, volatilizing the solvent, whereby the ingredient is left disseminated through the mix, and heating the mix with a vulcanizing agent to effect vulcanization.

4c- The process of forming a rubber composition'which consists in adding to rubber a composition ingredient in the condition, of a gel, mixing the gel With the rubber, volatilizing the solvent from the gel whereby the ingredient is left disseminated through the mix, and heating the mix with a vulcanizing agent to efi'ect vulcanization.

5. The process of forming a rubber composition which consists in adding to rubber a proteid' in solution, mixing the solution with the rubber, volatilizing the solvent whereby the proteid is left disseminated through the mix, and heating the mix with a vulcanizing agent to effect vulcanization.

6. The process of forming a rubber c0mposition which consists in adding to rubber a solution of animal glue, mixing the solution with the rubber, volatilizing the solvent whereby the glue is left disseminated through the mix, and heating the mix with a vulcanizing agent to effect vulcanization;

Z. The process of forming a rubber composition which consists in adding to rubber a wet precipitate of a composition ingredient, which precipitate has been formed in the presence of a protective colloid, mixing the resultant precipitate with the rubber, drying the mix, and heating the mix witha vulcanizing agent to effect vulcanization.

8. The process of forming a rubber composition which consists in adding to rubber conslsts in precipita a wet precipitate of barium sulfate, which precipitate has been formed in the presence of a colloidal gel, mixing the resultant pre cipitate with the rubber, drying the mix, and heating the mix with a vulcanizing agent to effect vulcanization.

9. The process 1f preparing a composition ingredient for rubber products, which ting such ingredient from a solution containing a gel-forming colloid, whereby the. coated with gel.

10. The method of preparing barium-- sulfate foruse as a composition ingredient in rubber products which consists in pre cipitating the barium-sulfate in a solution containing animal glue, whereby the nascent precipitate is coated with glue.

11. The process of forming a rubber composition whichconsists in adding to rubber a composition ingredient in the form of a precipitate carried by the liquid in which it was precipitated, mixing the carrier liquid and the precipitate with the rubber, volanascent precipitate is I tilizing the liquid, and heating the mix with a vulcanizing agent to effect vulcanization.

12. The homogeneous vulcanized product formed by adding'to rubber a composition ingredient in a fine state of subdivision and held by a carrier, liquid, mixing the liquid and ingredient held thereby with the rubber, driving off the liquid and heatingthe resultant dry mix with a vulcanizing agent to effect vulcanization.

13. The homogeneous vulcanized product formed by adding to rubber a proteid held by a carrier liquid, mixing the proteid and carrier liquid with the rubber, driving off the. carrier liquid, and heating the resultant dry mix with a vulcanizing agent to effect vulcanization,

14; The-homogeneous vulcanized product formed byadding to rubber animal glue formed into a gel with the rubber, driving 01f the Water, and heating the resultant dry mix with a vulcanizing agent to eflect vulcanization.

ROBERT C. HARTUNGQ by water, mixingthe gel 

